Low temperature poly-silicon (LTPS) TFT technology is a next-generations technology after Amorphous-Silicon (a-Si) TFT technology in a flat panel display field. The electron transfer rate of a conventional amorphous silicon material is 0.5 cm2/V·S only, while the electron transfer rate of a low temperature poly-silicon (LTPS) material may be up to 50-200 cm2/V·S, and therefore, as compared with a conventional amorphous-silicon thin film transistor liquid crystal display (a-Si TFT-LCD), a low temperature poly-silicon thin film transistor liquid crystal display (LTPS TFT-LCD) has advantages such as high resolution, fast response, high brightness and so on, and meanwhile, peripheral driving circuits may be fabricated on a glass base substrate as well, so as to achieve a purpose of integrating system on the glass substrate, and thus space and cost can be saved, and in addition, the low temperature poly-silicon TFT technology is a technical platform for developing an active matrix organic light emitting diode (AM-OLED), so that development of the low temperature poly-silicon TFT technology attracts more attentions in the industry.
Because the preparations process of a low temperature poly-silicon TFT array substrate is complex, there are needed often 10 to 11 times of photolithography process, which increases productions cost of a low temperature poly-silicon display device.